1. Field of the Invention
The present invention relates to a labeling machine of the portable type, and more particularly to a printing device for use with the labeling machine, wherein the printing device provides an averaged clear print upon a printing medium such as a label.
2. Description of the Prior Art
Generally, a labeling machine of the portable type (which will be referred to as "hand labeler") or a portable label printing and tagging machine has a platen made of a hard material, such as a metal plate or hard plastic, so that a printing medium, e.g., a label, placed on the platen may be stamped or printed with the plural types which are arranged on type rings or bands.
The aforementioned types are usually made of an elastic material such as rubber. Consequently, even if the type surfaces of the respective series of the type rings or bands of a printing head are inclined or become irregular or uneven due to either error in the molding or assembling processes or to wear after use, any protruding types are compressed or crushed by the elasticity of the types themselves, when they are pressed onto the surface of the label upon the platen during the printing operation. This flattens the types as a whole into contact with the label surface so that the prints obtainable are averaged clean as a whole.
On the other hand, types made of a relatively hard material, such as plastic, have recently been used because they can be produced more easily and at a lower cost, while being more durable than types made of rubber. For types of plastic or metal, there will be no crushing of the protruding types during the printing operation, e.g., when the respective series of the types are inclined or become irregular, because the material of the types has reduced elasticity. As a result, since the type surfaces at recessed positioned either fail to contact the label surface or only slightly touch it, they fail to print type indicia or the indicia become thin, making it difficult to attain clear prints as a whole.
Thinned or incomplete prints are acceptable if they are to be read by human eyes, but they are less acceptable in a POS (Point-Of-Sales) system, which requires clear and highly accurate prints because the prints have to be read out by means of an optical reader.